Prior to the present invention, there has existed a need by small manufacturers and as well by small businesses to maintain some or improved control over the number of machines running concurrently and/or the total number of machines permitted to run during any predetermined set period of time. Also, there has been the need to stagger the running of machines over a longer period of time, as contrasted to permitting too many run concurrently over a short period of time. Such matters are very important in the power company computation of total charge for the amount of electrical current used, such that by selectively permitting solely a few machines to run in according to predetermined priority, and by preventing concurrent running beyond predetermined limits, as regards a plurality of competing machines all driven by electrical power, substantial savings in operating costs may be made. While there have previously been some few devices serving some one or more of these functions, such machines have had disadvantages of not serving all such functions and/or more importantly such machines have been very complicated in their design and operation and parts thereof, resulting in costs of purchase far above the maximum limits that can be afforded by most of these small manufacturers and/or small business users of electrical energy. The importance of such control of operating costs such as cost of electrical power, has grown in magnitude recently by the notorious increases in costs of electrical energy which threaten the very economic existence of many of these manufacturers and/or small businesses which cannot afford to pay unlimited charges for electrical power total usage. Discussion of typical non-anticipating prior art is as follows.
U.S. Pat. No. 2,311,438 discloses a relay arrangement for the predetermined sequential operation of several pieces of electrical equipment with provision for the manual over-ride of the sequence if desired. The sequence can be changed by use of a switch at each mechanism location. It is used where several pieces of machinery are required to satisfy the demands of the operating means. For example, multiple water pump installation to maintain system water pressure. Where the conditions are satisfied, the equipment controlled shuts down in the opposite sequence form start-up. It requires a separate source of power to operate the invention thereof, the purpose being not the same nor are the results the same as that of the present Applicant's invention.
U.S. Pat. No. 2,712,101 discloses a relay interlock circuit--having priority levels which are assigned to relays shown with individual momentary switches-relay selected by a switch "locks" itself on and interrupts "lock-in" circuit path for all relays of lower "priority". As shown, it requires two separate sources of power. No means is shown for disabling top priority relay once it is energized. If lower priority relays are actuated while higher priority relays are "locked in", such lower priority relays will oscillate while attempt is made to actuate. The circuit has only one mode of operation for the disclosed invention thereof, but the purpose and the results are not the same as that of the invention of the present invention by the present Applicant.
The U.S. Pat. No. 3,066,227 device reduces electrical demand by dropping selected loads during the operation of a single, preferred "indispensable" load-operating means of preferred load (thermostat, switch, etc.); it operates a relay which, when operated interrupts power to another relay which drops the "dispensable" load or loads; the first relay also operates a third relay which turns-on the "indispensable" load. When its operating means returns to its original state, its system reverts to its original condition. The patent shows just two levels of priority and shows no mechanism to change the mode of operation, nor provision for expansion of the system and requires a separate source of power to operate the first relay--no mechanism being shown to overide the system, and the scope of the disclosed invention thereof is very limited, while the utility is somewhat analagous to that of the present invention. Also, the patent's device does not provide for any central monitoring of power consumption.
U.S. Pat. No. 3,339,079 discloses sequential addition and removal of generators on line, in response to load conditions, to maintain the smallest number of generators operating, each at close to maximum output level. It requires central monitoring of power consumption and a separate source of power to operate computer-like cuitry to make decisions and action them. Sophisticated and complicated and complicated and expensive mechanisms and structure are disclosed, as well as the purpose and method(mechanism) of operation not being the same as that of the present invention.
U.S. Pat. No. 3,359,426 discloses a relay circuit which prevents simultaneous operation of several loads. Actuation (by mechanism of momentary contact normally-open switch) results in shut-down of any previously actuated circuit. Attempt to activate more than one device results in shut-off of both. It requires separate source of power, as with prior patents. Only one mode of operation is disclosed, and the purpose is not the same, nor the result, as compared to the present invention, the patented device being apparently intended to operate related loads within a same common machine.
U.S. Pat. No. 3,443,114 discloses a relay circuit designed to prevent simultaneous operation of two or more loads, by incorporating timers to allow complete (timed) cycle; if a second load mechanism calls for operation, a second such load will wait until the first load finishes its cycle before beginning. At that point, the first device will then also wait until the second device's cycle is complete. There is also shown a "series" connection making use of solely one operating mechanism for two or more controlled loads, and requires also a separate source of power to operate timers. Thus, again, the purpose and results of the disclosed mechanism is not the same as that of the present invention.
U.S. Pat. No. 3,489,913 relates to an improvement to the inventions of U.S. Pat. No. 3,133,202 and U.S. Pat. No. 3,291,998; both previous patents monitor the power line to detect level of power consumption and, based on the level, sequentially switch on or off a number of loads (in a fixed priority of sequence) to prevent high peak consumption of electricity. The improvement shows an additional unit (cycler) with patch-cord connection to the original stabilizer, permitting a number of loads to share any given priority level by rotating the available time among the several loads. There is required a central monitoring of power consumption, and required separate power supply to operate the cycler which is basically a timer which steps through all possible input-output combinations repeatedly. There is no provision for individual over-ride from outside control, and is very complex in operation as well as being of a different mechanism of operation, even though the purpose of the invention thereof is somewhat the same as that of the present invention.
U.S. Pat. No. 3,538,391 discloses a load control sequencing system to prevent high peaks of electrical consumption. It uses central monitoring of total electrical consumption; when consumption rises, the connected loads are sequentially disconnected in a fixed ored of priority. Loads are sequentially reconnected in the reverse order of priority. It is a solid state system, and requires a separate source of power to a central control panel, and is a complex mechanism more suitable for large electrical installations; multi-position switch allows for changing of consumption level at which action of the system begins. While the results is somewhat the same, the mechanism or method of achieving the ends is totally different from that of the present invention.
U.S. Pat. No. 3,714,453 discloses a load control system similar to that of U.S. Pat. No. 3,538,391 except that central monitoring is by a modified demand or watt meter similar to the type used by the utility companies. It is a very complex system, using computer-like elements to make decisions based not only on the position of the demand meter needle, but also on the rate and direction of its motion; it is said to be able to "anticipate" what action should be taken to prevent high peak consumption. Very complicated mechanism which is expensive, is disclosed, providing for seasonal adjustment for the point at which action is taken. Such is better suited for large installations, not being the same as the present invention.
U.S. Pat. No. 3,769,520 discloses a load control system similar to U.S. Pat. No. 3,538,391 except providing mechanism for automatic adjustment of consumption level at which action takes place. Adjustment takes place in response to the needs of controlled equipment and/or central monitoring device. The centralized system requires separate source of power, and the mechanism is expensive and complex, more suited for large installations, and the mechanism being totally different from that of the present invention.
U.S. Pat. No. 3,814,947 discloses a "flip-flop" for alternately energizing of two separate loads (incandescent lamps). It depends upon changing impedance of the load due to the energization. It requires momentary interruption of power supply for reversal to take place. Purpose different from that of the present invention, it would have no utility for the present invention.
U.S. Pat. No. 3,872,371 discloses constant total power supply for several loads. Decreasing power delivered to one load permits increased power to be delivered to remaining loads from a common power source. Purpose of the patented invention is different and the results different and the mechanism different from that of the present invention.
U.S. Pat. No. 4,066,913 discloses the same as U.S. Pat. No. 3,066,227, except providing for more than two levels of "priority". No mechanism is provided for changing which loads are connected to which priority level. Once built, it is difficult to modify or expand. It uses a separate source source of power, and uses a central control box. In operation, the highest priority load in operation shuts-off all lower priority equipment. There is no provision for override. While the purpose and result (utility) appear to be substantially the same as for the present invention, the mechanism and complexity are much more complicated and expensive than for the present invention, the patented disclosed mechanism being better adapted for large company operation.
While there are other patents to circuitry that might superficially resemble that of the present invention, there is no analogy in utility and adaptation for Applicant's use; a major utility of the present invention arises from the use of basically simple and readily available equipment, and the simple design embodying the same, as hereinafter disclosed.